Manufacture of dyestuffs containing chromium



. e parts oi. w;

an and then allowed to cool.

particular tented Feb. 9, 1932 UNITED STATES PATENT OFFICE RHINE, GERMANY, ASSIGNORS T GENERAL. ANILINE WORKS, INC., OF NEW YORK,

N. Y A COBEORATION 01E DELAWARE MANUFACTURE OF DYESXTUFFS CONTAINING GHROMIUM No Drawing. Application filed February 17, 1928, Serial No. 255,175, and in Germany August 6, 1925.

- ture at which the dyestuffs are destroyed.

filter the present application is for the chromation oil? a specific class of dyestuiis under elevated pressure namely such dyestuffs as are obtainable by coupling a diazotized o-hy- (ll'OK -amino compound with a PYTZIZOlOIlG or sul tint-ion product thereof. Also in the case oil such initial dyestuflj's great advantages are experienced by carrying out the chromation under elevated pressure and in the time of heating, necessary for the formation of the chromium compounds is consiilerably reduced. As has been broadly stated alr d in the aforesaid application v tier. lie. "46, it often adiumiageous also 1' l in this specific case to subject the dyestuils containing; chromium so obtained to a subsequent treatment with alkaline agents in the manner described in the German Patent 4119,5325.

The following example will further jillustrate the nature of the said invention which however not limited thereto. The parts are by weight.

Eaiamplc parts of the axe dyestuffs, obtainable in the usual manner from diazotized 4l-nitro-2- aminiiphe1ioli-sulphonic acid and 3n1ethyll-phenyl-a-prrazolone, are stirred into 700 er and a solution oi? chromium tornmte coi esponding to 8 parts oi chromium oxid is added. The mixture is heated or 3 to il; hours to 120 centigrade in an enamelled autoclave provided with a stirrer, The chromium compound of the dyestuif is precipitated by the addition of common salt.

The product may be directly used for dye- .iue; after it has been dried or it may be converted into the sodium. salt which is more readily soluble in water by treatment with alkaline agents, such as sodium carbonate or caustic soda. The new dyestufl' dyes wool from an acid bath clear yellowish-orange shades of very good fastness.

The complex chromium compound of the dyestuil obtainable from diazotized 4ch1or- Q-amino-phenol-6-sulpho11ic acid and 3- methyl-1-phenyL5-pyrazolone which may be obtained in a similar manner under pressure, dyes wool very fast red shades.

iVhat we claim is 1. In the production of chromium C0111- pounds of o-hydroxyazo dyestuii's obtainable from an o-hydroxydiazo compound and a pyrazolone, the step which comprises heating an o-hydroxyazo dyestuff of the said kind with. a chromium compound capable of reacting therewith, in a closed vessel at a temperature sufliciently above 100 C. to produce superatmospheric pressure, but below the temperature at which the dyestuii' is destroyed.

2. The process of producing a chromiterous o-hydroxy-azo dyestui'l' which comprises heating the o-hydroxy-azo dyestufi' obtainable from diazotized l-nitro-2-aminophenol-6-sulphonic acid and 3-methyl-1-pl1enyl-5-pyraz clone with a chromium formats solution in a closed vessel at 120 C.

In testimony whereof we have hereunto set our hands.

HANS KAMMERER. KARL HOLZACH. 

